Fatto matematico: 4640 is the number of different score sequences of an 11-team round robin tournament.
Trivia: 4640 is a boring number.
Data storica: September 13th is the day in 1899 that Mackinder, Ollier and Brocherel make the first ascent of Batian (5,199 m – 17,058 ft), the highest peak of Mount Kenya.